A British official says a murderous attack near a London barracks is being investigated as a possible terrorist act. Police said two men attacked another man on Wednesday. One man was dead and two others were injured.

The attack took place in the street near a military barracks and the dead man was a British soldier, who was beheaded by the knife-wielding attackers.

According to eyewitness accounts, the attackers shouted “Allahu akbar” during their assault, and filmed the attack while it was in progress.

One witness reportedly said the men were “crazed, like animals” and carried large knives “like you would use in a butcher’s, they were hacking at this poor guy, we thought they were trying to remove organs from him.” It took more than 20 minutes for the authorities to arrive on the scene, he added.

British media released footage of one of the alleged attackers explaining his motives to the camera. “We swear by almighty Allah we will never stop fighting you,” the bloody-handed man says, along with several political statements, before walking back to the body of his victim, which can be seen sprawled in the street behind him.

According to witnesses, a group of women confronted the attackers and prevented them from mutilating the body of the victim or carrying out further attacks, the Telegraph reported. Officials praised the public response and announced an investigation into the lack of immediate police response to the incident.

British Prime Minister David Cameron called the killing “truly shocking” and said he had asked Home Secretary Theresa May to call an urgent meeting of the government’s emergency committee.

A British government official said the details that had emerged were indicative of a “terrorist-motivated attack.”

May said she had been briefed by Britain’s domestic security service, MI5, and by police on what she called a “sickening and barbaric” attack.

Britain’s Ministry of Defense said it was urgently investigating reports that a soldier was killed in the incident.

Police said armed officers responded to reports of the assault Wednesday afternoon just a few blocks from a military training barracks in southeast London.

Commander Simon Letchford said a number of weapons — including possibly a firearm — were used in the attack.

He confirmed that one man was found dead at the scene and that two men were shot by police and taken to separate London hospitals. One of them is in serious condition, according to London Ambulance Service.

A tent is erected near the scene of an attack in Woolwich southeast London Wednesday, May, 22, 2013 (photo credit: AP/Alastair Grant)

Live television images of the scene showed a trail of blood staining a pavement, cordoned off streets and crime scene investigators marking the scene.

David Dixon, head teacher of a nearby primary school, said police told him there was a “serious” incident. He said he saw body lying in the road outside.

He told the BBC that he then made sure children were inside and put the school into lockdown mode. He said he then heard shots fired.

The Independent Police Complaints Commission, which is called in when officers are involved in shootings, confirmed that it is investigating the incident, which took place near the Royal Artillery Barracks.

The barracks — which house a number of the King’s Troop Royal Horse Artillery and independent companies of the Grenadier and Coldstream Guards — were the site of shooting events during the 2012 London Olympics.